Each year hurricanes, nor'easters, and other extreme-wind storms result in billions of dollars in damage. While flooding caused by hurricanes receives greater attention, a significant portion of damage is the result of the high winds experienced by building structures that were not built to withstand such forces.
Residential homes, with their wood-frame construction and numerous windows, are most susceptible to wind damage. Often severe winds can literally tear roofs from homes because of pressure differences between the internal pressure of the house and the external pressures resulting from the high wind. The low pressure lift forces that result in most roof damage is caused by wind traveling further along one plane of a roof versus the other plane. This lifting force is similar to lifting forces experienced by an airplane wing. The severity of the lifting force is determined by the pitch of the roof.
Low pressure generally occurs on the side of roof opposite of wind direction. Thus the roof opposite the wind direction will experience lifting. This often results in damage or even catastrophic failure of the roof structure in cases where the wind speed is high enough. Hurricane force winds are anywhere from 74 mph, in a Category 1 hurricane, to over 156 mph, for a Category 5 hurricane. Such high winds can produce sufficient uplift forces to tear a roof from a structure.